Gonadotropin-releasing hormone (GnRH) is a neuroendocrine peptide synthesized in the neurovascular terminals of the hypothalamus. GnRH selectively binds specific receptors on membranes of the anterior pituitary gonadotroph cells to stimulate synthesis and releases of the gonadotropic hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH and FSH respectively stimulate gonadal production of sex steroids and gametogenesis. Due to its potential in treating sex hormone-dependent diseases such as prostate, ovarian, and breast cancer, GnRH analogs have received much attention. GnRH analogs can be generally classified as either agonists or antagonists. GnRH agonists stimulate the production of LH and FSH when agonists are used at therapeutic doses. GnRH antagonists competitively block the GnRH receptor to suppress bioactive LH, FSH and the resultant sex hormones.
Because of the therapeutic benefits of GnRH analogs, there is a need to provide pharmaceutical compositions of GnRH analogs that are suitable for oral administration, injectable administration and other forms of administration.